Copper continued complex, mechanism

The enzymes of this type that have been characterized contain some type of redox-active cofactor, such as a flavin (3), or a metal ion (heme iron, non-heme iron, or copper), or both (4-6). Our understanding of the mechanism of these enzymes is most advanced in the case of the heme-containing enzyme cytochrome P450. But in spite of the availability of a crystal structure of an enzyme-substrate complex (7) and extensive information about related reactions of low molecular weight synthetic analogues of cytochrome P450 (8), a detailed picture of the molecular events that are referred to as "dioxygen activation" continues to elude us. 

The research on the reaction mechanism of the oxidative polycondensation of 2,6-dimethylphenol (DMP) was also continued in the years around 1990. In several publications a Dutch research group reported on kinetic studies dedicated to the 02-promo ted polycondensation of DMP catalyzed by copper tetramethyl 1,2-diamino-ethane complexes [233-236] or by copper complexes of imidazole [237,238]. The speculative mechanistic scheme was based on dimeric copper complexes such as (147a) which were assumed to incorporate a DMP anion (147b) which was oxidized to yield a phenoxy cation and to coordinate another DMP molecule (148a). The growing step was then assumed to consist of a nucleophilic substitution at the phenoxy cation (149) with liberation of a reduced dimeric copper complex (148b). This complex was believed to be... 

---